Free piston type plunger



Jan. 28, 1969 E. K. MOORE. JR

Original Filed Feb. 28, 1966 FREE PISTONTYPE PLUNGER Sheet INVENTOR.

Ear/ K. Man/e; Jn

' /Warcas L Ba zes United States Patent 3,424,066 FREE PISTON TYPEPLUNGER Earl K. Moore, Jr., P.O. Box 2486, Odessa, Tex. 79760 Originalapplication Feb. 28, 1966, Ser. No. 530,514, now Patent No. 3,351,021,dated Nov. 7, 1967. Divided and this application Aug. 7, 1967, Ser. No.667,022 US. Cl. 92-193 6 Claims Int. Cl. F04!) 47/12; F16j 1/06 ABSTRACTOF THE DISCLOSURE A free piston type plunger having an impact responsivepacker section about a mid-portion thereof which is actuated to theclosed or opened configuration, respectively, as the plunger isdecelerate'd by a lower or upper stop means, respectively, of a gas liftwell. The plunger includes an upper body portion and a lower bodyportion. A mandrel is slidably received within the lower body portionand is attached to the upper body portion. The packer section iscircurnferentially disposed about the lower body portion and mounted forlimited movement in a manner whereby the packer is expanded radiallyaway from the mandrel when the plunger assumes the closed configuration,and wherein the packer is retracted radially towards the mandel when itassumes the opened configuration.

Cross reference to related applications This is a division of Ser. No.530,514; for Free Piston Pneumatic Arrestor and Control System; filedFeb. 28, 1966; for applicant Earl K. Moore, Jr. now Patent No.3,351,021; issued NOV. 7, 1967.

Background of the invention The use of gas lifts in producing an oilwell is a well known fluid recovery means and generally employs a freepiston type plunger which is actuated by the pressure of the gas fromthe producing formation so as to cyclically cause the piston within thetubing string to lift a slug of liquid from the oil bearing formation toa point of collection above the ground level. The free piston mustaccordingly reciprocate within the tubing string from one extremitythereof to the other. Generally, the pressure provided by the gas phaseof the oil-gas mixture will build up in magnitude over a period of time,and at a predetermined lapse of time, a motor valve control meanslocated at the outlet end of the tubing string will be actuated, usuallyin response to a timer mechanism, and generally predicated upon theknown history of the well, so as to open the motor valve which permitsflow from the outlet end of the tubing string, thereby establishing apressure differential across the plunger, and accordingly allowing theplunger to move upwardly through the tubing string, thereby bringingwith it a slug of liquid. When the plunger reaches the top of the tubingstring the upward movement thereof is arrested and the motor valveclosed. Soon thereafter the pressure across the plunger will equalize,and the plunger will fall by gravity to an abutment means located in thebottom of the eductor tube or tubing string, whereupon the plunger willthen rest against the lower abutment means until the pressure has againbuilt up to a suitable value, whereupon the motor valve will again openand the cyclic process will start over again.

A primary problem which has been recognized in conjunction with plungerlift apparatus is that the plunger in abutting the arresting apparatuslocated in the lubricator is subjected to a sudden deceleration. Thisdeceleration, in the past art, is generally provided by a bumper pad andspring arrangement. Such an arrangement generally causes the spring tostack at a high rate, thereby causing the 3,424,066 Patented Jan. 28,1969 "ice Summary of the invention It is therefore a primary object ofthe present invention to provide a free piston type plunger, sometimealso called a traveling plunger, or simply a plunger, which has anexpansible packer section that sealingly cooperates with a tubing wallof a gas well in a manner to improve the flow of fluid from the well.

Another object of the present invention is to provide a plunger havingan expansible packer section which is outwardly expanded to enable theplunger to assume the fluid lifting configuration, and which is inwardlycontracted to enable the plunger to free-fall through a column of fluid.

A further object of the present invention is to provide a free pistonassociated with a gas lift well with a packer section which is actuatedfrom the sealed to the unsealed condition, and vice versa, by the actionof a centrally located longitudinally extending mandrel.

A still further object of this invention is to provide a free piston orplunger that incorporates a unique packer section thereon that retractsupon impact within the lubricator and expands upon impact with the lowerbumper pad.

The above objects are attained in accordance with the present inventionby the provision of a free piston type plunger fabricated in a manneressentially as outlined in the above abstract, and as defined by theannexed claims.

The various features of novelty which characterize my invention isparticularly pointed out in the claims that form a part of thisspecification. A complete understanding of this invention may be hadfrom the following detailed description and the accompanying drawingsreferred to therein, illustrating the novel features by which the aboveobjects set forth above are carried out.

In the drawings:

FIGURE 1 is an enlarged elevational view showing the plunger of thepresent invention;

FIGURE 2 is another view of the device of FIGURE 1, and shown in adifferent operative condition as compared to FIGURE 1;

FIGURE 3 is a cross-sectional view of the device seen in FIGURES 1 and2;

FIGURE 4 is a crosssectional view taken along lines 44 of FIGURE 3; and

FIGURE 5 is a perspective view of one of the segments of FIGURES 1through 4.

Referring now to the drawings in greater detail, the invention asillustrated therein disclosed a traveling plunger, or free piston, 200which is intended to be placed in an eductor tube, or oil well tubing,where the plunger reciprocates from a lowermost position deep within theearth to an uppermost position above the surface of the earth, all in amanner as explained in the above parent patent application.

The instant novel device may also be used in applications where the freepiston 200 is cycled occasionally so as to remove parafiin or gyp fromthe tubing string, for lowering gas-oil ratios, to extend the flowinglife of a free flowing well, to increase efficiency on gas lift, forunloading gas wells, and to minimize emulsion.

Looking now to the details of FIGURE 1 in conjunction with the remainingfigures of the disclosure, there is seen therein a pneumatically drivenplunger or free piston 200 having a metal packer section 202 about themidportion thereof comprised of three individual metal packer segments204 retained in place by upper body portion 206 and slip ring 205. Lowerbody portion 210 carries a mandrel 212 telescoped therein thatthreadedly engages upper body portion 206 as indicated by numeral 213.The mandrel and upper body portion are pinned together at 214 so as tomaintain upper body portion 206 and the mandrel 212 rigidly attachedtogether. Lower body portion 210 telescopingly fits about the mandrel212 and is adapted to reciprocate within the annulus 230 formed betweenupper body portion 206 and the upper extremity of the mandrel.

The mandrel maintains the metal packer section and the slip ring inproper alignment with the remaining structure. The lower portion of themandrel is provided with an enlargement 220 that provides a lowerabutment means and cooperates with enlarged counter bore of the lowerbody at 224 that accordingly provides a stop means for the shoulder 222of enlarged portion 220. The slip ring 205 is pinned to the mandrel bypin 226 which is received within an aperture that is drilleddiametrically through the slip ring and mandrel. The pin 226 is adaptedto carry the slip ring 205 along with the mandrel within the limitsprovided by the upper and lower extremities of slot 228 located in thesecond diameter 211 of the lower body portion 210.

The lower body portion 210 is further provided with a third reduceddiameter portion 209 that is adapted to carry the metal packer section202 about the outer periphery thereof. The third reduced diameter 209 isprovided with a groove 240 that is adapted to cooperate with a lug 242located on the inner periphery of the metal packer section. The lug 242provides a seal to prevent gas flow through the tool and is adapted toreciprocate between the lower and upper extremities of the groove 240.The third reduced portion of the lower body portion is provided withapertures 244, 246 equally spaced about the outer periphery thereof andin alignment with similar apertures located within each segment of themetal packer section as amply illustrated by numerals 244, 246. Thealigned apertures provide a chamber within which a compressed spring 248is located. The spring is maintained in compressed condition so as toresiliently urge the metal packer segments in an expanded directionradially away from the reduced diameter portion 209. The upper extremityof the mandrel 212 is provided with two dimples 252, 254 that cooperatewith spring loaded ball 256 located within aperture 258 that resilientlyholds the mandrel 212 in one of the two positions relative to the upperbody portion 206. The spacing between dimples 252, 254 is equal inlength to the length of travel permitted by slot 228, groove 240, andannulus 230.

The upper body portion 206 has a first counter bore 270 and a secondcounter bore 272 that are tapered together at 274 and provided with ashoulder at 276. The annular shoulder 276 provides an abutment for theannular shoulder 207 formed between the lower body portion fourthreduced diameter 208 and the lower body portion third reduced diameter209.

The segments of metal packer 202 are provided with a lip at 282 and aretapered at 280 so as to cooperate with the upper body portion at secondcounter bore 272 in a manner to be urged from an expanded to a retractedposition as the metal packer section reciprocates longitudinally of thelower body portion third reduced diameter 209. The lower extremity ofeach metal packer segment 290 is retained in proper position by the slipring 205 which is provided with a taper 260 between cylindrical face 262and 264 so as to urge the metal packer section from an expanded to aretracted position in a manner similar to the before described action inconjunction with lip 282 as it travels longitudinally along the thirdreduced diameter 209 of the lower body portion.

The segments 204 of the metal packer section 202 are fabricated so as toprovide an upper and lower recess 216, 217, that receives upper andlower fingers 218, 219 respectively to thereby provide a tortuous pathfor any fluid flowing across the metal packer section of the tool andaccordingly provide an effective seal. The metal packer section isprovided with ribs 266 that are adapted to ride against the insidesurface education tube of the well and accordingly provide a scaledrelationship between the pneumatically driven plunger and the wall ofthe education tube.

In operation, the pneumatic plunger will be resting on the bottom bumperof the education tube (not shown) and the metal packers section thereofwill be in expanded condition and accordingly in sealing relationshipwith the inside wall of the eduction tuba. When the motor valve (notshown) above the surface of the ground level is moved to the openposition, the pressure differential produced across the plunger willdrive the plunger in an upward direction, whereby the plunger willaccordingly lift any fluid contained above the plunger and within theeduction tube due to the seaaling relationship between the packer andthe tube. During the travel of the plunger from the bottom bumper to theupper pneumatic, the metal segments 204 of the metal packer section 202will ride against the inner peripheral surface of the eduction tube andprovide an effective seal therewith. When the plunger reaches the upperlimits of the eduction tube and enters the lubricator, the upper bodyportion 206 will strike the bumper pad or upper stop means, andaccordingly the plunger will be rapidly decelerated to a complete stop.The momentum of the plunger will drive the packer segments 204 and thelower body portion 210 in an upward direction relative to the mandrel,the upper body portion 206, and the slip ring 205. The metal segments,because of the cooperation between the upper tapered surfaces 274, 280and the lower tapered surfaces 260, 261, will asume the retractedposition in opposition to the resilient springs 248. Since the plungeris now of reduced diameter, and accordingly no longer provides a sealedrelationship in conjunction with the eduction tube, the plunger will nowbe free to fall by gravity to the bottom of the eduction tube where itwill then strike the bottom bumper or stop means. The enlarged lowermandrel abutment 220 will receive the blow from the bottom bumper,whereupon the packer section and lower body portion 210, because of itsinertia, will continue to travel relative to the mandrel and accordinglywill return to the expanded position which permits tapered portion 280,261 of the packer segments to be driven downwardly with respect to theadjacent tapered portions whereby the packer segments are again inexpanded position and accordingly in sealed relationship with theeductor tube, whereupon the traveling plunger 200 is then ready for itsnext cycle of operation.

The novel traveling plunger, because of the retractable spring loadedsegments, rides across the pipe joints of the eductor tube with aminimum wear since the segments of the metal packer section are free toexpand and retract in conformity to the inside diameter of the eductortube through which it is traveling. Hence the present novel plungerprovides for a long life because of the lack of criticality between itsoutside diameter as compared to the diameter of the eductor tube. Thenovel plunger may be used in any existing gas lift installation, andwhile it is of rugged construction, the novel plunger is preferably usedin conjunction with the pneumatic arrestor described in Patent No.3,351,021; issued Nov. 7. 1967. This particular pneumatic arrestor ispreferred because its improved pneumatic action lengthens the usablelife of any plunger.

1 claim:

1. A free piston type traveling plunger comprising an upper body portionand a lower body portion;

a mandrel slidably received within said lower body portion and attachedto said upper body portion; said lower body portion having a portionthereof received within said upper body portion;

a packer section mounted for limited movement and circumferentiallydisposed about said lower body portion;

means responsive to deceleration located at each extremity of saidpacker section for expanding said packer section radially away from saidmandrel when said traveling plunger is abruptly decelerated duringdownward travel, and for retracting said packer section radially towardssaid mandrel when said traveling plunger is abruptly decelerated duringupward travel thereof.

2. The traveling plunger of claim 1 wherein;

said mandrel includes a free end and a fixed end;

said upper body portion being rigidly attached to said fixed end;

said packer section including a series of segments circumferentiallydisposed about said lower body portion and displaced in interlockingrelationship with respect to each other;

and means urging said segments radially outward from said lower bodyportion.

3. The plunger of claim 1 wherein said means responsive to decelerationincludes a tapered end portion at each end of said packer sectionlocated about the outer periphery thereof, and a similar tapered portionlocated on the lower extremity of said upper body portion thatcooperates with one of said tapered end portions of said sections;

a slip ring attached to said mandrel and including a tapered portionthat cooperates with the other of said tapered portions of said packersection, whereby:

impact of said upper body portion and impact of said mandrel against astop means provides for the above recited retracting and expanding ofthe packer section.

4. The plunger of claim 1 wherein said upper body portion is rigidlyafiixed to said mandrel; said upper body includes an outwardly taperedlower portion peripherally enclosing an upper portion of said packersection and adapted to retract said packer section;

means including a slip ring attached to said mandrel and including aninwardly tapering upper portion peripherally enclosing a lower portionof said packer section; said slip ring adapted to retract said packersection;

said lower body portion being slidably received within said packersection and slidably enclosing a portion of said mandrel;

said mandrel having a lower portion thereof extending below said lowerbody portion, whereby:

impact of said upper body portion and impact of said depending lowermandrel portion provide for the before stated function of expansion andretraction of the packer section.

5. The plunger of claim 1 wherein said packer section includes amultiplicity of interlocking segments circumferentially disposed aboutsaid lower body portion;

said packer section including an upper end portion and a lower terminalend portion;

said upper end portion having means forming an upwardly and inwardlysloped portion; said lower terminal end portion having means forming adownwardly and outwardly sloped portion;

said upper body portion including a circumferentially disposed skirtwhich receives said upper end portion therein;

said mandrel including a slip ring attached thereto andcircumferentially disposed in slidable relationship about said lowerbody portion and said lower terminal end;

said slip ring further including an upwardly and inwardly dependingportion which cooperates with said lower terminal end, whereby:

the sloped portions of said slip ring, said upper end portion, saidlower terminal end portion, and said skirt jointly cooperate to providethe recited function of the means responsive to deceleration.

6. The plunger of claim 1 wherein said packer section includes amultiplicity of interlocking segments; each segment being longitudinallydisposed with respect to said mandrel, means for radially biasing eachsegment outwardly from said mandrel:

each segment including upper and lower depending end portions whichcooperate with said means responsive to deceleration, and spaced apartedge portions;

one edge portion having means forming recesses therein, the spaced apartedge portion having means forming depending fingers thereon, saidfingers of one segment being received by said recess of an adjacentsegment to thereby provide a tortuous flow path across the plunger whenthe packer is in the expanded configuration.

References Cited UNITED STATES PATENTS 2,674,951 4/1954 Zaba 103-522,728,398 1,2/1955 Taylor 103-52 X 2,850,339 9/1958 Vincent 103-52 X2,884,861 5/1959 Vincent et a1. 103-52 2,937,598 5/1960 Brown 103-523,090,315 5/1963 Milton 103-52 3,105,555 10/1963 Villalon 166-1753,229,768 1/ 1966 Lunebring 166-170 3,249,056 5/ 1966 Lyles 103-523,251,418 5/1966 Condra 166-174 X 3,304,874 2/1967 Lyles 103-52 CARROLLB. DORITY, JR., Primary Examiner.

US. Cl. X.R.

